1. Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
2. Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
3. Department of Surgery, Dong-A University Medical Center, Busan, Korea.
4. Department of General Surgery, Cheil General Hospital & Women's Healthcare Center, Seoul, Korea.
5. Department of Surgery, St. Vincent's Hospital, The Catholic University of Korea College of Medicine, Suwon, Korea.